Production of unsaturated ketones



otherknownrnethodsl i u l v I Thefollowing examplesfurther illustrate the mven tion,

United States Patent PRODUCTION OF UNSATURATED KETONES Henry Peter Cr'ocker, Horusea, England, assiguor to The Distillers Company Limited, Edinburgh, Scotland, a

British company No Drawing. Filed July 14, 1960, Ser. No. 42,754 Claims priority, application Great Britain Aug. 21, 1959 2 Claims. (Cl. 260-595) The present invention relates to the production of organic compounds and in particular to the production of unsaturated ketones.

The present invention is a process of producing an unsaturated ketone having the formula R o=oH.oHi.0Hi.o0.R

l which comprises heating an allyl acetoacetate having the formula 7 in cont-act with an aluminium compound having the formula wherein R and R are alkyl groups of 1 to 2 carbon atoms or hydrogen atoms, R, is an alkyl group of l to 2 carbon atoms and R is an alkyl group of not more than 5 carbon atoms, R and R are alkyl or alkoxy groups of 1 to 2 carbon atoms, and n is one of the integers 1 or 2. Where more than one of any of the groups R R or R is present in the formula of the aluminium compound, they may he' the same or difierent groups.

The allyl acetoacetate may be heated in contact with the aluminium compound with advantage at an elevated temperature, preferably at a temperature from 100 to 250 C. The temperature used in any particular embodiment of the invention depends; on the nature of the allyl acetoacetate heated; if, for instance, the allyl acetoacet-ate I is methylbutenyl acetoa-cetate, it may be heated at a temperature from to 170;Q, preferably from to ,i C. .0 The allyl acetoacetate is conveniently heatedwith thev aluminium compound in'a'n apparatus which enables a steady stream of-icarbon-dioxide to be evolved and removed;- V p v l f a The aluminium compound used in the process of the invention may be, for example, an aluminium mono (acetylacetouate) di-(alkoxide), aluminium di-(acetylacetm fnate) mono-(alkoxide), aluminium v mono-(methylaceto- 1-acetate):di (a1koxide), aluminium di-(methylacetoacetate) mono(alko xide), aluminium mono-(ethylacetoacetate) di- (alkoxide), aluminiumdi-(ethylacetoacetate) mono (alkox-' ide),: aluminium di-(alkoxide)1mono-(2:4-pentanedione)'"or aluminiuni' di-(alkoxide) mono-(ethylmalonate).f ,Thef alkoxide is preferably a'rnethoxidaethoxide;propoxideor butoxide. "I'healuminium cj'oinpoundfmay, for example, v i-be prepared-by reacting-thecalculated;stoichiornetric:proportions of the 'correspondingjalurninium trialkoxidejand. I

' acetylacetone or alkyl a'ce'toacetate, removing the' alkanol .theialuminium compound; orby produced and recover wherein R and R are each selected-from the group con I "si sting of -alkyl groups of 1 to v2 carbon atoms and hydro-i 3,101,375 Patented Aug. 20, 1963 Example 1 Methylbutenyl acetoacetate was heated with aluminium di-(isopropoxide) mono-(ethylacetoacet-ate) as catalyst in a reactor fitted with a stirrer and a gas outlet, at from 140 to 170 C. so that a steady stream of carbon dioxide was evolved from the pyrolysis of the methylbutenyl acetoacetate, leaving 'methylheptenone in the reactor. The concentration of catalyst was 16 millimoles per mole of methylbutenyl acetoacetate. w

The molar yield of methylheptenone produced based on the methylbutenyl acetoacetate, was 77.5%.

As a comparison, methylbutenyl acetoacetate was heated under the same conditions except that no aluminium compound catalyst was present; the yield of methylheptenone was 66% based on the methyl-butenyl acetoacetate.

Example 2 Methylbutenyl acetoacetate produced from 2,332 parts by Weight of crude methylbutenol, containing 2,178 parts by weight of methylbutenol, was mixed with 120 parts by weight of aluminium di-(isopropoxide) mono-(ethylacetoacetate) and the mixture was heated at 170 C. The concentration of catalyst was 16 millimoles per mole of methylbutenyl acetoa cetate.

After purifying the product by distillation, 2,521 parts by weight of methylheptenone were obtained, the molar yield, based on the methylbutenol reacted, was 83.8%.

I claim:

1. A process of producing an unsaturated ketone having the formula:

' R -C=GH-CHz-CHz-CO-R Ilia which comprises heating at an elevated temperature in the, t range of about 100 to 250 C an allyl acetoacetate having the formula: -r I i in contact an aluminum compound having the for;

, gen atOmS,1R3' is an alkyl group of 1 to 2 carbon atoms,

R and R5 are each selected from the group consisting of alkyl.groups:of .1 lto, 2 carbon-atom'sand alkoxy groups rof which the alkyl partfhas l to -2 carbon atoms, R is 'an 7 alkyl group ofnot more than 5 carbon atoms and n is one oftheintegers1and 2.

L at za- 'temperature fr'p 7 to -17 0 "QC 7 j I 2. sA-process claimed in claim lwhereirithe allyl aceto-i iacetatel is methyibutenyl :aeetoacetate andgwherein the 'cetoacetate. is contacted with the aluminum co pou ReierencsCited in the fjthispateu UNlTED'ES TATiSS PATENTS"; 

1. A PROCESS OF PRODUCING AN UNSATURATED KETONE HAVING THE FORMULA: 